The present invention relates generally to metal working and more particularly to a clinching tool.
It is well known to join sheet metal workpieces together by way of a clinch joint. Such a clinch joint is formed by a punch and die deforming workpieces in an interlocking manner. Exemplary clinch joints and tooling are disclosed in the following U.S. Patents and Patent Publication Nos.: 2006/0196034 entitled “Sheet Fastening Apparatus and Method;” U.S. Pat. No. 7,003,861 entitled “Tool Assembly Employing a Flexible Retainer;” U.S. Pat. No. 6,092,270 entitled “Die for Forming a Joint;” and U.S. Pat. No. 5,435,049 entitled “Apparatus for Joining Sheet Material;” all of which were invented or co-invented by the inventor of the present application and are incorporated by reference herein.
Various actuators have been used to advance punches relative to clinching dies. One such conventional actuator is a pneumatically powered motor, disclosed in U.S. Pat. No. 3,730,044 entitled “Fluid Operated Apparatus” which issued to Sawdon on May 1, 1973, and is incorporated by reference herein. Furthermore, there has been a desire to reduce the width of workpiece flanges in order to save material costs, weight and space. Such a reduced width flange, however, makes fastening the workpieces together at the flange much more difficult given the size and function of traditional clinching tools.
In accordance with the present invention, a clinching tool is provided. A further aspect of the present application locates an anvil and/or movable die members closer to one lateral outside surface of a die body than the opposite lateral outside surface. In another aspect, a tool is employed which can create a clinch joint on a narrow width workpiece flange. In yet another aspect, an offset clinch die and pneumatic tool are employed. Another aspect of the present application includes a die body having an anvil and two linearly movable die members which essentially surround a lateral outside surface of the anvil when in inward positions. A method of clinching is also disclosed.
The present invention is advantageous over prior constructions since the present clinching tool is capable of creating a clinch joint on a much narrower width workpiece flange. Furthermore, the present clinching tool is advantageously robust, durable and protects the internal moving parts within a die body. The present clinching tool is also less complex than various traditional constructions and is thereby relatively simple to disassemble for maintenance and cleaning. Moreover, the specific die blade and die body shapes used with various aspects of the present clinching tool advantageously deter die blade rotation, misalignment and binding during clinching yet provide interlocking engagement between the die blades, anvil and die body. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.